1. Field of the Invention
The present invention relates to semiconductor devices and more particularly to a semiconductor device having a function of setting a test mode.
2. Description of the Background Art
Conventionally, a semiconductor device has a test mode circuit to set a test mode which is an operation mode for test facilitation. When a prescribed test mode is set by the test mode circuit, the semiconductor device operates according to the prescribed test mode. Thus, the inner state of the semiconductor device can be tested easily.
However, the conventional test mode circuit in a semiconductor device is formed so that a prescribed test mode is set by one setting operation. It is therefore impossible to freely combine several test modes (test operations) by a test program.
When the conventional test mode circuit is used, a test mode is entered by one setting operation and therefore a false test mode may be set according to the state of an unexpected input signal.